Crack Resistance of High-Strength Steel and Breakage of a Gas Pipeline

Abstract

The available methods for identifying the type of failure of a 15–20 MPa gas pipeline used to evaluate the crack resistance of X90, X100, and Х110 high-strength steels cannot reliably predict the arrest of a main crack over the length of two or three pipes. Ductile fracture mechanics is used to determine the length of the plastic zone, the stress state, rate and degree of strain, and damage of the metal at the front of a growing macrocrack. A new fracture criterion based on plasticity diagram is proposed. The new approach to the evaluation of the crack resistance of steel reduces the growth rate of the main crack to less than the decompression rate of a gas pipeline after breakage and arrest of the main crack.